(CNN) -- When your smartphone makes it so easy to connect to the Internet, why bother firing up a clunky desktop or laptop computer?
Two-thirds of cell-phone owning Americans use their phones to surf the Web and check e-mail, according to the latest study from the Pew Internet & American Life Project. That's double the amount from 2009, when only 31% of people said they used their phones to go online.
For a growing segment of people, phones aren't just a secondary way to check the news or send off a quick e-mail. According to Pew, 21% of phone owners use their devices as their primary way of accessing the Internet, more than PCs and tablets.
Since Pew began tracking Internet and phone usage in 2009, the numbers have steadily risen year-over-year. First there were the youthful early adopters, then it spread to older age groups. This year, biggest jump in online phone-owners was among 50- to 64-year-olds.
The groups most likely to own a smartphone are still the same people who are most likely to access the Internet from their phones. The tech-savvy 18- to 29-year-old set is the most likely to go online from a phone, as are people with a college degree or higher, or people making more than $75,000 a year.
Mobile Web use also is higher among minorities. Three-quarters of African-American and 68% of Hispanic phone owners are going online from their handsets, while just 59% of white phone owners are doing the same.
A whopping 91% of American adults have cell phones and a little more than half of those are smartphones.
Smartphones are built for accessing the Internet and apps -- so much so that making a phone call on the devices can seem like an afterthought. Touchscreen Android, iOS, Blackberry and Windows Phone devices are replacing one-trick feature phones, and are changing the way Americans access the Internet in the process.
Each year smartphones get faster, the screens sharper and apps better. Internet connections are also speeding up, both though cellular networks and available Wi-Fi networks.
Not every phone owner uses a fancy smartphone to surf the Web, however. People are also going online from their feature phones between texting, phone calls and games of "Snake." Surfing the Web on these devices is an impressive feat given the limited controls available.